Microbial Testing 

Food producers and processors engage in regular testing for pathogens and toxins in their raw materials and products to ensure the proper functioning of their food safety management systems. They also conduct environmental monitoring to identify and eliminate sources of foodborne pathogens in the facility. This helps to reduce the risk of food contamination and its consequences, ranging from product recalls to outbreaks.

Environmental pathogen monitoring is considered a proactive approach to microbial food safety, as it can identify potential sources of pathogens before they cause contamination in products. These programs are particularly useful because finished product testing alone is not a reliable method of ensuring food safety, as the occurrence of foodborne pathogen contamination in finished products is typically rare.
 

Process Control Testing

Basic environmental pathogen monitoring programs serve as tools to verify pathogen control strategies or to trace product contamination events and usually involve the testing of high-risk areas, such as food contact surfaces. Risk managers often implement advanced monitoring programs that are based on process control testing. These inform preventive control measures, such as seek and destroy programs, that further limit contamination events from the environment. Process control testing is aimed at early warning sites, where presence of a pathogen can be identified before it reaches food contact surfaces or the product. Positive results at an early warning site have no regulatory compliance implications, as the presence of a pathogen does not necessarily indicate a systematic failure of the food safety system. However, they should suggest caution and stringent follow-up testing. Process control testing frequently involves the determination of so-called index microorganisms (e.g., Listeria spp., Staphylococcus spp.), as methods for specific pathogens include extensive confirmation steps.

Sampling is critical for accurate results. Failure to sample correctly, or to understand the variability associated with sampling, may invalidate the overall test result and lead to a faulty conclusion. Sampling is the most important source of errors in microbial testing, as microorganisms tend to spread unevenly in their environments. This is even more so in the case of surfaces, with most sampling devices being able to recover only a small fraction of the microbial population that is targeted. Choosing adequate sampling materials and applying the correct technique will allow for reliable results.
 

Collection of Samples from Surfaces

While there is no universally accepted protocol for sampling, there are a variety of methods commonly used as well as standards wtih general requirements (e.g. ISO 18593). Common methods for sample collection involve the use of various devices such as swabs, sponges, or cloths. Wet-dry swabbing is a well-established method for the collection of environmental surface samples and is widely used in food production and processing facilities to detect pathogens or to monitor sanitation or other operational programs. Swabbing is also a non-destructive method employed to sample mammalian carcasses in the meat sector.